[PATCH 5.12 011/127] scsi: qedf: Add pointer checks in qedf_update_link_speed()

Greg Kroah-Hartman
2021-05-24T16:04:25Z

From: Javed Hasan <jhasan@marvell.com>

[ Upstream commit 73578af92a0fae6609b955fcc9113e50e413c80f ]

The following trace was observed:

[ 14.042059] Call Trace:
[ 14.042061] <IRQ>
[ 14.042068] qedf_link_update+0x144/0x1f0 [qedf]
[ 14.042117] qed_link_update+0x5c/0x80 [qed]
[ 14.042135] qed_mcp_handle_link_change+0x2d2/0x410 [qed]
[ 14.042155] ? qed_set_ptt+0x70/0x80 [qed]
[ 14.042170] ? qed_set_ptt+0x70/0x80 [qed]
[ 14.042186] ? qed_rd+0x13/0x40 [qed]
[ 14.042205] qed_mcp_handle_events+0x437/0x690 [qed]
[ 14.042221] ? qed_set_ptt+0x70/0x80 [qed]
[ 14.042239] qed_int_sp_dpc+0x3a6/0x3e0 [qed]
[ 14.042245] tasklet_action_common.isra.14+0x5a/0x100
[ 14.042250] __do_softirq+0xe4/0x2f8
[ 14.042253] irq_exit+0xf7/0x100
[ 14.042255] do_IRQ+0x7f/0xd0
[ 14.042257] common_interrupt+0xf/0xf
[ 14.042259] </IRQ>

API qedf_link_update() is getting called from QED but by that time
shost_data is not initialised. This results in a NULL pointer dereference
when we try to dereference shost_data while updating supported_speeds.

Add a NULL pointer check before dereferencing shost_data.

Link: https://lore.kernel.org/r/20210512072533.23618-1-jhasan@marvell.com
Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Javed Hasan <jhasan@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/qedf/qedf_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
index cec27f2ef70d..e5076f09d5ed 100644
--- a/drivers/scsi/qedf/qedf_main.c
+++ b/drivers/scsi/qedf/qedf_main.c
@@ -536,7 +536,9 @@ static void qedf_update_link_speed(struct qedf_ctx *qedf,
if (linkmode_intersects(link->supported_caps, sup_caps))
lport->link_supported_speeds |= FC_PORTSPEED_20GBIT;

- fc_host_supported_speeds(lport->host) = lport->link_supported_speeds;
+ if (lport->host && lport->host->shost_data)
+ fc_host_supported_speeds(lport->host) =
+ lport->link_supported_speeds;
}

static void qedf_bw_update(void *dev)
--
2.30.2